I LOVE the colors, they really pop. And they really add to the sci-fi feel to the piece. What I really like is that you seem to have captured this scene with minimal amount of brushwork and its awesome. How long did it take to do this piece?

Composition and colors work here very well, it's seen in the thumbnail. Really beautiful! I'd suggest diving in and making better distinctions between the background, mid ground and foreground. Adding a bit more details too to help the eye focus. Keep at it, you're doing great so far